Oncologic outcomes of surgically managed primary pelvic soft tissue sarcoma; tumour biology or surgical constraints of the true pelvis?

Abstract

BackgroundPelvic soft tissue sarcomas are rare. Potentially curative resection remains challenging due to anatomical constraints of true pelvis and tumour spread through various anatomical hiatus. We sought to review the oncological outcomes of surgically managed cases at our centre and determine whether outcomes differ for patients with localised (limited to pelvis) versus extensive disease (with extra-pelvic extension). MethodsSixty-seven patients who underwent surgical resection with curative intent at the centre for primary, non-metastatic, WHO intermediate to high-grade soft tissue sarcoma of the true pelvis from January 2012 through January 2020 were analysed. Establishment of the extent of disease was made by review of pre-treatment imaging and surgical notes. Oncologic endpoints examined were resection margin, recurrence rate, disease-free and overall survival. ResultsRates of complete oncological resection and disease control were similar for tumours with localised or extensive disease. On logistic regression analysis, tumour grade, and a negative resection margin (R0) correlated with the risk of recurrence (p=<0.05). On further multinomial analysis, R0 resection was associated with improved local control, but not metastatic relapse (p = 0.003).5-year local recurrence-free and distant metastasis-free survival were 61.3% and 67.1%, respectively. Five and 10-year overall survival were 64% and 36%, respectively. Age >50 years and high tumour grade were associated with a worse outcome (p < 0.05). ConclusionsWhen potentially curative surgery is performed for pelvic sarcoma, disease-extent does not influence oncologic outcomes. While a complete oncologic resection determines the risk of local recurrence, tumour grade and metastatic relapse remain primary prognostic determinants for overall survival.